Association Between Glomerular Filtration Rate, Free, Total, and Percent Free Prostate-specific Antigen

• Published in: Urology (Ridgewood, N.J.) Vol. 76; no. 5; pp. 1042 - 1046
• Main Authors: Joseph, Djenaba A, Thompson, Trevor, Saraiya, Mona, Werny, David M
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.11.2010; Elsevier
• Subjects: Adult; Aged; Biological and medical sciences; Glomerular Filtration Rate; Humans; Male; Medical sciences; Middle Aged; Nephrology. Urinary tract diseases; Prostate-Specific Antigen - blood; Prostatic Neoplasms - diagnosis; Renal Insufficiency, Chronic - blood; Renal Insufficiency, Chronic - physiopathology; Urology; Prostate specific antigen; Nephrology; Association; Free form; Total; Tumoral marker; Urology; Glomerular filtration rate
• ISSN: 0090-4295; 1527-9995
• DOI: 10.1016/j.urology.2009.05.100

Objectives To determine the relationship between glomerular filtration rate (GFR) and free prostate-specific antigen (fPSA), percent-free PSA (%fPSA), and total PSA (tPSA) in patients with diminished kidney function not on dialysis, using nationally representative data. Methods A total of 3782 men aged ≥ 40 years who participated in the National Health and Nutrition Examination Survey 2001-2006, and who met eligibility criteria for PSA testing were included in the final study population. GFR (mL/min/1.73 m2 ) was calculated using the Modification of Diet in Renal Disease equation 7 and categorized as ≥ 90, 60 to < 90, and 15 to < 60. Distribution of tPSA, fPSA, and %fPSA were estimated by GFR category and by age and race. Multivariate linear regression models were fit to determine the adjusted relationship between GFR and tPSA and %fPSA after adjusting for age, race, and body mass index. Results The multivariate linear regression analysis showed that GFR had a linear relationship with tPSA that was of borderline significance. There was a significant nonlinear relationship between GFR and %fPSA ( P <.001): increased GFR was associated with a decrease in %fPSA for GFR levels below 90 [eg, change in %fPSA = −2.67 (95% CI −3.56, −1.77) for a GFR of 85 as compared with 65; P <.001]. The decline in %fPSA with increasing GFR was nonsignificant for GFR levels above 90. Conclusions Our finding that renal function as measured by GFR is negatively associated with %fPSA has potential implications for use of this test in men with renal disease.